1. Field of the Invention
The invention relates to an automatic device for producing a cooled semi-liquid food product, more specifically soft-ice, milk-shake or yoghurt, starting from a composition, which automatic device comprises a pump, a suction conduit connected at one end to the pump and, during operation, to a reservoir with the composition, a pressure conduit connected at one end to the pump and the other end of which forms a draught end for the food product, a cooling element, of which the cooling part forms the evaporator of a cooling circuit and the cooled part is located in said pressure conduit and a cleaning device comprising, in turn, a cleaning conduit, one end of which fits on a closable opening of the pressure conduit at or in the vicinity of the draught end, a closeable drain conduit connecting to this cleaning conduit, means for blocking the drain conduit and a liquid supply means.
2. Discussion of the Prior Art
Automatic devices are known for producing soft-ice or milk-shakes. A liquid composition is pumped from a reservoir, usually a supple bag, by means of the pump which also provides for an injection of air and thus the whipping of the mixture. The thus whipped mixture is consequently cooled in the cooling element. A rotating screw-shaped scraping is mounted around the cooling part of this element, scraping the whipped mixture over the cooling part and pushing it towards the draught end. Soft-ice is cooled in such a way that ice formation occurs around the cooling part.
Such automatic devices are also used for distributing yoghurt. With these automatic devices, the whipping with air is not necessary, and the pump does not inject air but is only used for pumping the yoghurt composition from the reservoir to the cooling element.
It is generally known that the bacteriological cleanness of the food products produced by the above-mentioned automatic devices sometimes leaves much to be desired. This is caused by a lack of regular and effective cleaning of the parts coming in contact with the food product or the composition. In order to clean the known automatic device, the suction conduit has to be disconnected from the reservoir and has to be put consecutively in one of more reservoirs with liquids such as a cleaning liquid, a so called sanitary liquid and a rinsing liquid.
A device of this kind is disclosed in U.S. Pat. No. 2,977,097. In this device, the suction conduit is inserted in the reservoir with the composition during operation. For cleaning, this suction conduit is directly connected to a water reservoir, which can be time consuming as the suction conduit is not provided with a connecting piece. For cleaning, a cleaning conduit is connected with one end to the draught or dispensing end of the pressure conduit and with the other end to the air-inlet pipe of the pump. During cleaning, water is circulated by means of the pump with a limited flow rate and only through the pressure conduit and the air-inlet pipe, and not through the suction conduit. Cleaning is consequently not effective. Moreover, if other liquids for cleaning have to be used, such as a detergent, the cleaning conduit has to be disconnected.
U.S. Pat. No. 3,273,585 discloses a flushing apparatus for dispensing freezers. The dispensing freezers are however of the type without a pump wherein the mix or food product is delivered by gravity. Such freezers comprise an open mix storage tank on top and thereunder the freezing cylinder. Cleaning may take place when the mix storage tank is empty by introducing water through a spout mounted above the storage tank. Circulation of the water is not possible. Therefore cleaning is not effective.